Production of copper cakes and sheet bars



June 7, 1932. F. L. ANTISELL ET AL 1,862,074

PRODUCTION OF COPPER CAKES AND SHEET BARS Filed July 9, 4

' surface of the resulting sheets,

Patented June 7, 1932 'uNrrEo sTAT s I PATENT ogrlcs FRANK L. .ANTISELL, OF PERTH AMZBOY, NEW JERSEY, AND CHARLES G. MULLINEAUX, OF ANSONIA, CONNECTICUT, ASSIGNOBS TO ANACONDA COPPER MINING COMPANY,

A coar'orta'rron .or uoiv'rana PRODUCTION OF COPPER CAKES AND SHEET BARS Application filed m 9,

For the rolling of copper sheets and bars, the copper is first cast in what is called a cake of suitable size and shape to be con'- veniently handled and to fit the rolls, weighing around 225 pounds, oblong in plan and a few inches thick. What is called the standard cake, for example, is 14 x 17 x 2 inches thick and is cast in this form with the 2 inch dimension vertical and with a slight taper at the sides to permit removal from the mold, usually of copper formed with a lunger. 1

The top face of such a cake takes a certain set or slight roughness in solidifying. Also there is a certain amount of sweating on the sides and ends of the cake. This is the formation of fine particles like drops of copper on the otherwise smooth face of the cake, generally ascribed to the shrinkage of the cake at the outside while its center is still molten and the exudation of fine drops of copper through to the surface.

In subsequent rolling of such cakes, the is sometimes bad because of the set or roughness on the top. Also the generally red sheen of the surface is marred by spots or zones of a yellowish color, familiar to experts and due apparently to oxidation.

We propose to avoid these disadvantages by casting the cake differently. At the same time we have found in our improved cake certain other advantages referred to in detail hereinafter. i

The accompanying drawing illustrates an embodiment of the invention.

Fig. 1 is a side elevation of cast position;

Fig. 2 is an edge elevation of the same;

Fig. 3 is a plan thereof; Fi 4 is a diagram illustrating the rolling of a eet bar.

Figs. 5 and 6 are respectively a cross-section and a longitudinal section of the mold filled with the cast copper.

We propose to cast the cake with its ends at the top and bottom in copper molds with the taper necessary for easy removal. This Wlll produce a cake as shown with smooth sides 1 and edges 2.and a smooth lower end face 3,

the cake in the 1924. Serial No. 724,983.

and an upper end face 4 having the set or roughness involved in the solidifying of the casting.

We have found after considerable experimentation that cakes cast in this way can be produced without sweating on the sides and edges. In practice we have made such cakes 16 inches long by 10 inches wide at the narrow end and about 4 inches thick, with a taper on the sides and the edges of about %ths of an inch, casting the metal at the usual temperatures and obtaining smooth sides and edges without any sweating.

Such a cake when rolled into a sheet bar 5 (Fig. 4) has a uniform surface without any of the yellowish spots that have appeared on such bars rolled from the standard cakes. In

bars and plates rolled from standard cakes such yellowish spots have apparently shown an inferior resistanceto corrosion. They are probably due to segregation of impurities in the top of the standard cake. Such impuri ties set up galvanic action with the copper which hastens corrosion by-the well known phenomena of local action. With bars and plates rolled from our improved cake there is a noticeable improvement in resistance to corroslon.

There is also a very great saving in scrap for two reasons. First, the face of the new cake constitutes the rear end of the bar or sheet which is rolled. An irregularity on this end means a comparatively small cropping 6. The forward end is drawn out to a tapering shape requiring a comparatively short cropping 7.

The second advantage over the standard cake is that the new cake can be rolled with the aid of universal rolls. We have illustrated diagrammatically horizontal rolls 8 for the top and bottom faces and vertical rolls 9 for the side edges ofthe bar. Theuse of such edge rolls is made ossible by the smoothness of the edges 2 o the new cake and their freedom from sweating or other irregularity. The consequence is that no cropping of the bar 5 is required along its sides. With the standard cake above described, the sides universal mill could not well be used and the lit) have been so rough that a rolled product has been both wa vy and rough at the sides requiring cropping at-both sides edge has prevented the use of edge rolls and resulted in a rolled bar with one edge very rough and irregular and the other wavy so that it had to be crop ed as well as the ends. Such cakes were also adly sweated on their J sides and ends. In our experiments, we have found that'such sweating is apparently due to the comparativelyslightdepth of the metal in" the mold. From the depth of the standard cake, about 4 inches, up to about 7 or 8 inches, the sweating occurs in substantial extent. Above 8 inches the sweating either disappears or is much reduced, an

at about 12 or 14 inches depth it generally disappears entirely.

While we cannot say with certainty-that it is so, we'think the cause of the sweating may lie in the difference in the depth and the freezing curve of the copper and its eutectoid in the two cases of a comparatively shallow and a comparatively dee casting.

In rolling copper longitu inally there is incidentally a lateral flow which increases the width from 5 to 10%, and irregularly where edge rolls are not used to rectify it; the' crop with these old style cakes has been approximately seven times the with the new cake herein escribed.

The discussion above is based on the use of refined copper containing say 99.95% copper and 0.04% oxygen. The invention, however, is applicable with advantage to copper of other degrees of purity.

The cakes referred to are to be distinguished from copper billets. These are generally round or square cross-section shapes usually accurately machined, the shrinkage of the billet being depended on to release it from the mold. y

The cakes of the present invention are cast inmolds of copper, the interior surfaces of whichv are formed by means of tapered plungers presentin faces "which are sufiiciently smooth for t esubsequent rolling op eration on the cakes, but which are not smooth tauantity necessary construction avoids the occurrence of the cracks in the mold which would form fins on the corners of the cake and would interfere with. the subse uent rolling operations. Though we haved ticularity of detail certain embodiments of our invention, yet-it is not to be understoodl therefrom that the invention is restricted to the particular embodiments disclosed. Various modifications may be made by those skilled in the art without de arture from the invention. asdefined in the ollowing claims.

What we claim is:

1. Acopper cake of the character described for rolling into sheets and sheet bars, cast endwise in tapered form' so that 'itsupper end constitutes the set face of the copper and its sides and edges are smooth, said cake being approximately 10 x 16 2: 4 inches.

2. A copper cake of the character de-' scribed for rolling into sheets and sheet bars cast endwise in tapered form so that its upper end constitutes the set face of the copper and its sides and edges are smooth, the width, length and thickness of such cakes being substantially in the ratio of 10 x 16 x 4 3. The method of producing a copper sheet bar which includes in combination the following steps,-casting a cake with certain faces and edges in cont-act with the sides of a tapered one-piece mold which produces smooth surfaces on said faces and edges and rolling said cake out into a bar with rolls engaging said smooth surfaces.

4. The method of producing a. copper sheet bar which includes in combination the following steps,casting a cake with certain escribed with greatpar- I faces and edges in contact with the sides of with rolls engaging said smooth surfaces.

In witness whereof, we have hereunto signed our names.

FRANK L. ANTISELL. CHARLES o. MULLINEAUX.

enough to permit" the removal of the cakes .except with the aid of the tapered shape.

Such a mold is indicated in Figs. 5 and 6 With side walls 10, end walls 11 and bottom 12, the top being 0 en'for pouring in the metal. The taper o the side and end walls is suificient to permit removal of the cake without splitting the mold, and the integral 

